I've been recommending Let the Right One In for weeks to anybody who will listen to me. It's seriously good. Probably the best vampire movie ever made. BTW, contrary to what Dartful said in his synopsis, I don't think she's pretending to be 12. I think it's more complicated than that. But y'all will have to see it for yourselves to know what I'm talking about. It's only in limited release, so there are likely no theaters in your city playing it, but there's a decent DVD screener rip floating around the torrent networks.
BTW, to give you an idea of how good this movie is, it's only in limited release and already there's a Hollywood remake in the works.

The guy who directed Cloverfield is making an American Let The Right One In, to be released in 2010, I think.
edit: retarded grammar